Lilly's Q4 profit falls on strong dollar, charge

Eli Lilly has been on a roller coaster in the wake of patent expirations, Chairman and CEO John Lechleiter told CNBC on Friday after the drugmaker reported a 41 percent fall in quarterly profit.

Lilly was hurt by a stronger dollar and a one-time charge related to a restructuring program.

The company said it earned $428.5 million, or 40 cents per share, in the fourth quarter ended Dec. 31 from $727.5 million, or 67 cents per share, a year earlier. Its stock price was up slightly in premarket trading Friday. (Click here for the latest price.)

"It's been up and down. As you know when you lose a patent in this business the generic entry comes very quickly and you essentially lose all of that revenue overnight," Lechleiter said in a "Squawk Box" interview.

To deal with the bleed, the company has been investing in research and development and replenishing its pipeline of drugs, he said. He noted that Lilly received approval for four new products from the Food and Drug Administration in the past year.

With more than half of its sales generated outside the United States, the strengthening dollar impacted sales significantly, Lechleiter said. The company, however, did not change its full-year earnings guidance of $3.10 to $3.20 per share on a non-GAAP basis.

"Even though our revenues are coming down from those sales and countries that have weakened currencies versus the dollar, we actually gain a benefit from the cost of our inventories that sit outside the United States, so our gross margin actually increases, and that tends to balance things out."